The invention relates to the technical field of battery management, and discloses a device for estimating battery SOC (State-of-Charge). The device comprises a processor. The processor is configured to judge whether the battery enters a charging tail end and estimate the SOC value of the battery in a condition in which the battery is judged to enter the charging tail end and according to the detected battery current I, the battery voltage V and the preset corresponding relationship among the battery voltage V, the current I and the SOC value under different multiplying power. The precision of the SOC value estimated by the device is greatly improved, and damage to the battery due to overcharging can be prevented.